General Commissioning Issues

  

 

 

  Issue
Outstanding Outstanding OP issues from 2009
Maximum energy Do we/can we drop the physics energy from 7 TeV?
de-Gauss versus Nominal Do we start with a de-Gauss cycle for the main dipoles?
450 GeV Collisions

Will be provided for a limited period only (2/3 shifts, maximum a weekend) during the commissioning for 7 TeV

Common view of the experiments: such a run is not required by the experiments.
However, collisions at 900 GeV would be useful, mostly for time alignment.
A short period with such beam conditions is therefore interesting (up to a few shifts, i.e. in the noise of the commissioning schedule), provided these beam conditions are safe (no compromise on machine & experiment protection) and stable beam conditions declared.
The experiments would not require their magnets to be ON for this short 900 GeV run.
Experiments' solenoids Off for initial commissioning (up to first ramp attempts). Can then be brought on and left on after coupling checks.
Experiments' dipoles Off for initial commissioning. Need dedicated commissioning at 450 GeV and in the ramp (bump closure etc.). Switching off should be possible thereafter, and is potentially required.
Can we track a solenoid trip with beam? In principle yes.
 
Combined ramp and squeeze Can we think of doing a combined ramp and squeeze during commissioning? No
Beam Commissioning tolerances
Magnets